mset std001 03 std002 01 std003 03 std004 02 std005 01

RPUSH students 001 002 003 004 005

sort students by std*

pfadd dayone "huang" "wang"  "yao"   "feng"  "feng"  "ma"    "ma"    "sun"   "hu"    "zhou"  "yao"   "feng"  "huang"  "yao"   "wang"  "huang" "zhou"  "sun"   "zhao"  "yao"  

pfadd dayone "ma"   "feng" "zhou" "hu"   "wang"